The invention relates to a heart pacemaker with a clock pulse generator and shaping circuit for supplying the stimulation pulses in addition to an operating voltage generator, particularly a battery, wherein the shaping circuit comprises a series arrangement of capacitors which are chargeable in parallel and dischargeable serially.
A heart pacemaker of this type is known, for example, from the U.S. Pat. No. 4,050,004. This heart pacemaker functions with a battery voltage of approximately 2.5 V. Given a total of four capacitors, there derives an output voltage of approximately 10 V given parallel charging and serial discharging. Such an output voltage, however, is not always optimally adapted to the actual ambient conditions of the pacemaker. It is often the case that a pacemaker is desired whose output amplitude is variable according to prescribable need. For example, a step-shaped course of the stimulation amplitude can be desirable for the purpose of measuring the stimulus threshold of the pacemaker-assisted heart. Under certain conditions, other courses of the amplitude of the stimulation pulses can be desirable for other purposes. Overall, however, the heart pacemaker should always be laid out in terms of energy in such manner that the battery is loaded as little as possible after implantation, so that a longer useful life derives for the implanted pacemaker. For this reason, too, the pacemaker should be as variable as possible in the output amplitude of its pacemaker pulses.